Metals (Chemistry)

Metal + Oxygen = Metal Oxide

Metal+ Water = Metal Hydroxide + Hydrogen

Metal + Steam = Metal oxide + Hydrogen

Acid + Metal = Salt + Hydrogen

Rusting happens when oxygen and water are present. Also, salt and acids speed up the process.

There are two ways to prevent rusting, these are called Physical barrier and Sacrifical Protection.

Physical Barrier is when you prevent either water or oxygen, a way of this is covering something in paint.

Sacrifical Barrier is when you attach a more reactive metal on top of another to prevent it from rusting. Hence the name sacrifical. 

There is another way which is a mix of both ways, this is called galvanising. This is when you apply zinc to a metal which prevents it from rusting.